Vlachou Maria Evangelia, Legros Juliette, Sellin Cécile, Paleressompoulle Dany, Massi Francesco, Simoneau Martin, Mouchnino Laurence, Blouin Jean
Centre de Recherche en Psychologie et Neurosciences, Aix-Marseille Université, CNRS (UMR 7077), Marseille, France.
Maria Evangelia Vlachou, Centre de Recherche en Psychologie et Neurosciences, Aix-Marseille Université, 3 place Victor Hugo, Marseille, 13003, France.
Sci Rep. 2025 Apr 29;15(1):14959. doi: 10.1038/s41598-025-99503-w.
Traditionally, touch is associated with exteroception and is rarely considered a relevant sensory cue for controlling movements in space, unlike vision. We developed a technique to isolate and measure tactile involvement in controlling sliding finger movements over a surface. Young adults traced a 2D shape with their index finger under direct or mirror-reversed visual feedback to create a conflict between visual and somatosensory inputs. In this context, increased reliance on somatosensory input compromises movement accuracy. Based on the hypothesis that tactile cues contribute to guiding hand movements when in contact with a surface, we predicted poorer performance when the participants traced with their bare finger compared to when their tactile sensation was dampened by a smooth, rigid finger splint. The results supported this prediction. EEG source analyses revealed smaller current in the source-localized somatosensory cortex during sensory conflict when the finger directly touched the surface. This finding supports the hypothesis that, in response to mirror-reversed visual feedback, the central nervous system selectively gated task-irrelevant somatosensory inputs, thereby mitigating, though not entirely resolving, the visuo-somatosensory conflict. Together, our results emphasize touch's involvement in movement control over a surface, challenging the notion that vision predominantly governs goal-directed hand or finger movements.
传统上,触觉与外部感知相关联,与视觉不同,它很少被视为控制空间运动的相关感觉线索。我们开发了一种技术,用于分离和测量触觉在控制手指在表面上滑动运动中的作用。年轻人在直接或镜像反转的视觉反馈下用食指追踪二维形状,以在视觉和体感输入之间制造冲突。在这种情况下,对体感输入的更多依赖会损害运动准确性。基于触觉线索在与表面接触时有助于引导手部运动的假设,我们预测,与使用光滑、刚性手指夹板抑制触觉时相比,参与者用裸手指追踪时的表现会更差。结果支持了这一预测。脑电图源分析显示,当手指直接接触表面时,在感觉冲突期间,源定位体感皮层中的电流较小。这一发现支持了以下假设:响应镜像反转的视觉反馈,中枢神经系统选择性地抑制了与任务无关的体感输入,从而减轻了视觉-体感冲突,尽管没有完全解决。总之,我们的结果强调了触觉在表面运动控制中的作用,挑战了视觉主要支配目标导向的手部或手指运动的观念。